"Summa Theologica, Parts I-II (Pars Prima Secundae) from the Complete American Edition" is an important philosophical and theological work of St. Thomas Aquinas, one of the most outstanding figures of the Church. In this book, the author systematically explains the main principles of the Christian faith, substantiates the ideas about divine grace, man and the sacraments. The first and second parts of "Summa Theologica" belong to the most important works in medieval philosophy and theology. This book will help the reader to better understand Christian doctrine and spirituality, as well as to ponder the eternal questions of life and faith.